Capacity Improvement of 3D-OCDMA-PON Hybrid System Next Generation Using Weight Zero Cross Correlation Code
A new coding method for optical code division multiple access (OCDMA) is proposed, referred to as three-dimensional spectral/temporal/spatial single weight zero cross-correlation code. (3D-SWZCC). This method is intended for next generation passive optical networks or NG-PON systems, with the advantage of higher capacity and zero cross-correlation in order to suppress multiple access interference (MAI). previous 2D-SWZCC code used only spectral and spatial encodings however 3D-SWZCC includes a temporal aspect as well. This design also addresses challenges in OCDMA systems such as Multiple access interference effects (MAI), limited capacity and Phase-induced intensity noise (PIIN). Comparing 1D, 2D and 3D code, active user counts increase respectively from 68, 157 to 454 and code lengths from 68, to 171 and 273.
This method is also compared against other 3D codes from different studies, such as Perfect Difference (PD), PD/multi-diagonal (PD/MD), dynamic cyclic shift/multi-diagonal (DCS/MD), and Pascal’s triangle zero cross-corellation (PTZCC), which the proposed method is believed to outperform in PIIN and system capacity. A quality factor of 6dB is observed and a lower BER value under 10^-9. Based on the results it is estimated that the single mode fiber (SMF) length of next generation OCDDMA-PON (NG-OCDMA-PON) systems could extend to 122 Km without the need of amplifiers while maintaining data rates of 0.722 Gb/s, allowing high data rates for users with long SMF lengths of 10, 30 and 50 Km. MAI was observed to be successfully mitigated.